Such a magnetic resonance examination system is known from the US-patent application U.S. 2003/0206015.
The known magnetic resonance examination system has a control unit which automatically determines system-specific acoustic and mechanical resonances. Resonant oscillations are caused by pulsed operation of the gradient coil. In particular, periodically repeated gradient pulses (i.e. pulsed gradient magnetic fields) cause a forced mechanical oscillation of the magnetic resonance examination system. These gradient pulses cause eddy currents in structures surrounding the gradient coil and due to interaction with the main magnetic field exert (Lorentz) forces to cause these structures to move. All structures that are mechanically coupled, move or vibrate due to these forces. When periodically repeated gradient pulses are applied, forced mechanical oscillation of the system can occur and resonant amplification occurs if excitation occurs at the natural resonant frequencies of the mechanically coupled structures. When the superconducting coils of the main magnet are excited to oscillate, then increased evaporation occurs of Helium that is employed to cool the superconducting coils below their superconducting critical temperature. The excitation of mechanical or acoustic resonances is dependent on the imaging sequences in which gradient pulses are switched. Based on these dependencies the imaging sequences can be limited so that an excitation of mechanical resonances no longer occurs. In the known magnetic resonance examination system this dependency is obtained by forming a resonance curve as a function of the time spacing of the gradient pulses.